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  1. /*
  2.  * Copyright (c) 2006 Jakub Jermar
  3.  * All rights reserved.
  4.  *
  5.  * Redistribution and use in source and binary forms, with or without
  6.  * modification, are permitted provided that the following conditions
  7.  * are met:
  8.  *
  9.  * - Redistributions of source code must retain the above copyright
  10.  *   notice, this list of conditions and the following disclaimer.
  11.  * - Redistributions in binary form must reproduce the above copyright
  12.  *   notice, this list of conditions and the following disclaimer in the
  13.  *   documentation and/or other materials provided with the distribution.
  14.  * - The name of the author may not be used to endorse or promote products
  15.  *   derived from this software without specific prior written permission.
  16.  *
  17.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27.  */
  28.  
  29. /** @addtogroup libc
  30.  * @{
  31.  */
  32. /** @file
  33.  */
  34.  
  35. #include <as.h>
  36. #include <libc.h>
  37. #include <unistd.h>
  38. #include <align.h>
  39. #include <sys/types.h>
  40. #include <bitops.h>
  41.  
  42. /**
  43.  * Either 4*256M on 32-bit architecures or 16*256M on 64-bit architectures.
  44.  */
  45. #define MAX_HEAP_SIZE   (sizeof(uintptr_t)<<28)
  46.  
  47. /** Create address space area.
  48.  *
  49.  * @param address Virtual address where to place new address space area.
  50.  * @param size Size of the area.
  51.  * @param flags Flags describing type of the area.
  52.  *
  53.  * @return address on success, (void *) -1 otherwise.
  54.  */
  55. void *as_area_create(void *address, size_t size, int flags)
  56. {
  57.     return (void *) __SYSCALL3(SYS_AS_AREA_CREATE, (sysarg_t ) address,
  58.         (sysarg_t) size, (sysarg_t) flags);
  59. }
  60.  
  61. /** Resize address space area.
  62.  *
  63.  * @param address Virtual address pointing into already existing address space
  64.  *  area.
  65.  * @param size New requested size of the area.
  66.  * @param flags Currently unused.
  67.  *
  68.  * @return Zero on success or a code from @ref errno.h on failure.
  69.  */
  70. int as_area_resize(void *address, size_t size, int flags)
  71. {
  72.     return __SYSCALL3(SYS_AS_AREA_RESIZE, (sysarg_t ) address,
  73.         (sysarg_t) size, (sysarg_t) flags);
  74. }
  75.  
  76. /** Destroy address space area.
  77.  *
  78.  * @param address Virtual address pointing into the address space area being
  79.  *  destroyed.
  80.  *
  81.  * @return Zero on success or a code from @ref errno.h on failure.
  82.  */
  83. int as_area_destroy(void *address)
  84. {
  85.     return __SYSCALL1(SYS_AS_AREA_DESTROY, (sysarg_t ) address);
  86. }
  87.  
  88. /** Change address-space area flags.
  89.  *
  90.  * @param address Virtual address pointing into the address space area being
  91.  *  modified.
  92.  * @param flags New flags describing type of the area.
  93.  *
  94.  * @return Zero on success or a code from @ref errno.h on failure.
  95.  */
  96. int as_area_change_flags(void *address, int flags)
  97. {
  98.     return __SYSCALL2(SYS_AS_AREA_DESTROY, (sysarg_t) address,
  99.         (sysarg_t) flags);
  100. }
  101.  
  102. static size_t heapsize = 0;
  103. static size_t maxheapsize = (size_t) (-1);
  104.  
  105. static void * last_allocated = 0;
  106.  
  107. /* Start of heap linker symbol */
  108. extern char _heap;
  109.  
  110. /** Sbrk emulation
  111.  *
  112.  * @param incr New area that should be allocated or negative,
  113.                if it should be shrinked
  114.  * @return Pointer to newly allocated area
  115.  */
  116. void *sbrk(ssize_t incr)
  117. {
  118.     int rc;
  119.     void *res;
  120.    
  121.     /* Check for invalid values */
  122.     if (incr < 0 && -incr > heapsize)
  123.         return NULL;
  124.    
  125.     /* Check for too large value */
  126.     if (incr > 0 && incr+heapsize < heapsize)
  127.         return NULL;
  128.    
  129.     /* Check for too small values */
  130.     if (incr < 0 && incr+heapsize > heapsize)
  131.         return NULL;
  132.    
  133.     /* Check for user limit */
  134.     if ((maxheapsize != (size_t) (-1)) && (heapsize + incr) > maxheapsize)
  135.         return NULL;
  136.    
  137.     rc = as_area_resize(&_heap, heapsize + incr, 0);
  138.     if (rc != 0)
  139.         return NULL;
  140.    
  141.     /* Compute start of new area */
  142.     res = (void *) &_heap + heapsize;
  143.  
  144.     heapsize += incr;
  145.  
  146.     return res;
  147. }
  148.  
  149. /** Set maximum heap size and return pointer just after the heap */
  150. void *set_maxheapsize(size_t mhs)
  151. {
  152.     maxheapsize = mhs;
  153.     /* Return pointer to area not managed by sbrk */
  154.     return ((void *) &_heap + maxheapsize);
  155. }
  156.  
  157. /** Return pointer to some unmapped area, where fits new as_area
  158.  *
  159.  * @param sz Requested size of the allocation.
  160.  *
  161.  * @return Pointer to the beginning
  162.  *
  163.  * TODO: make some first_fit/... algorithm, we are now just incrementing
  164.  *       the pointer to last area
  165.  */
  166. void *as_get_mappable_page(size_t sz)
  167. {
  168.     void *res;
  169.     uint64_t asz;
  170.     int i;
  171.    
  172.     if (!sz)
  173.         return NULL;   
  174.  
  175.     asz = 1 << (fnzb64(sz - 1) + 1);
  176.  
  177.     /* Set heapsize to some meaningful value */
  178.     if (maxheapsize == -1)
  179.         set_maxheapsize(MAX_HEAP_SIZE);
  180.    
  181.     /*
  182.      * Make sure we allocate from naturally aligned address.
  183.      */
  184.     i = 0;
  185.     if (!last_allocated) {
  186.         last_allocated = (void *) ALIGN_UP((void *) &_heap +
  187.             maxheapsize, asz);
  188.     } else {
  189.         last_allocated = (void *) ALIGN_UP(((uintptr_t)
  190.             last_allocated) + (int) (i > 0), asz);
  191.     }
  192.  
  193.     res = last_allocated;
  194.     last_allocated += ALIGN_UP(sz, PAGE_SIZE);
  195.  
  196.     return res;
  197. }
  198.  
  199. /** @}
  200.  */
  201.